70 The Bulletin 



potasTi per acre, while on two other plats two and three times the normal 

 quantities were given, or 20 and 30 pounds of actual potash per acre 

 respectively. On basis of the normal fertilizer mixture this would 

 represent 5.7 and 7.5 per cent of potash in the mixture. 



The results are not uniform for the two fields, the most profitable 

 application being slightly in favor of 5 pounds of potash per acre for 

 Field A and slightly in favor of the use of 20 pounds of potash in Field 

 E. The largest average increase in yield of seed cotton as well as the 

 greatest profit per acre, was obtained from the plats receiving 20 pounds 

 of potash (100 pounds of manure salt) per acre with the regular quanti- 

 ties of nitrogen and phosphoric acid employed in the mixtures. 



Effect of Varying Quantities of Fertilizer on Yields. — This part of 

 the experiments was planned to show the effect of increasing and de- 

 creasing the normal (IST P K equals 400 pounds of a fertilizer mixture 

 containing 7 per cent phosphoric acid, 214> per cent potash and 21/2 per 

 cent nitrogen) fertilizer application on the yields of cotton. The appli- 

 cations Avere at the rate of 200 pounds per acre (^/^ IST P K) ; 400 

 pounds per acre (jST P K) ; 600 pounds per acre (11/2 N" P K) ; 800 

 pounds per acre (2 IST P K) ; 1,200 pounds per acre (3 IST P K). The 

 results on the two fields and the averages of these fields are quite uni- 

 form in showing increased yields and increased profits for the several 

 increases in the amounts of fertilizer up to 600 pounds per acre. On 

 an average of the results of the tests on both fields the use of 800 and 

 1,200 pounds of the fertilizer mixture per acre gave a greater increase 

 in value of total crop (lint and seed) over cost of fertilizer than did 

 the use of 200 or 400 pounds per acre of the same mixture. The 

 heavier applications, properly proportioned, have not only yielded the 

 largest yields and profits per acre, but in all probability left the land in 

 a more productive state. The results that may be secured from these 

 plats in later years will be helpful in throwing light on the importance 

 of large immediate returns by heavy fertilization and the results such 

 practice will have on the permanent productivity of the soil. Too little 

 attention is given by farmers generally to the matter of the permanent 

 producing power of their soils. 



RESULTS WITH CORN AT RALEIGH. 



Effect of Nitrogen, Phosphoric Acid, Potash, and Lime in Combina- 

 tion. — The experiments, the results of which are presented in Table 

 VTI, were planned to show the effect on the yield of corn of nitrogen 

 (!Nr), phosphoric acid (P), and potash (K), when two of the constitu- 

 ents w^ere applied together, as nitrogen and phosphoric acid (N P), 

 nitrogen and potash (I^ K), and phosphoric acid and potash (P K), 

 and when all three of these fertilizer constituents were applied to make 

 a complete fertilizer (N P K) ; also to test the effect of lime (L) alone 

 and when used in connection with a complete fertilizer (N P K L). 



The results are shown in yields of bushels of shelled com and pounds 

 of stover per acre for the several years, average yields, average increases 

 over the unfertilized (O) plats, which represent the effect of the fer- 

 tilizer applications, the value of the increase, the cost of the fertilizer, 

 and the value of the increased vield of corn and stover and of corn alone 



